This is probably related to whether one should capitalize Internet or not. I am looking for the correct spelling of wifi when referring to a wireless connection to the Internet. I want to tell the users of my iPhone app that they cannot use their cellular network to watch the HD videos.

If I use the capitalized and hyphenated version as seen on Wikipedia, will I be referring to the Wi-Fi brand rather than the concept of wifi?

"Wi-Fi" is a trademark of the Wi-Fi Alliance and the brand name for products using the IEEE 802.11 family of standards.

Some dude on Meta.stackoverflow made this claim with no explanation:

WiFi" is a bit better than "wifi" as it asserts the etymology, compare history of usage of "hifi" from which it derives. – Steve-o Aug 29 at 3:59

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    The Wi-Fi Alliance is just a trade association. They won't come knocking on your door in the middle of the night if you use their terminology. They're only interested in shutting out comptetition from any major global manufacturers who don't want to join them. Anyway, you've answered your own question by the mere fact that you happily wrote wifi twice in the first paragraph before wondering about capitalisation/hyphenation. Use what comes naturally to mind. Sep 9, 2011 at 0:10
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    My experience (non-native speaker from Europe) is: "WiFi" is rarely used, most people/places refer to it as "WLAN". I'm curous: does anyone else observe this outside of the US? In German language text I see "WLAN" being used exclusively and in English language text around Europe there seems to be a strong tendency towards "WLAN". Sep 9, 2011 at 6:17
  • @Joachim: WLAN is uncommon in Swedish (which is a Germanic language). I suspect the Nordic languages borrow more frequently from English than the ones further south. We also don't dub movies. :) Sep 9, 2011 at 10:40
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    This reminds me very much of this question: Is “blah blah blah” the most common spelling? Sep 14, 2012 at 14:46
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    @Matthew: This was nearly 3 years ago, and I honestly can't remember for certain, but I think it's unlikely I personally specified "Too Localised" (which is no longer available). I probably said it was "Not Constructive" (also no longer available), which would be in line with the comment I made at the time. And it just so happened TL was cited more often by the other 4 closevoters. IMHO the question is utterly pointless, because no-one is "in charge" of defining correct usage here, and the idea of the Wi-Fi Alliance "owning" that particular representation is frankly risible. Jun 23, 2014 at 20:03

11 Answers 11


Since you have an iPhone app and it would seem that Apple/iPhone use the term "Wi-Fi" throughout then I would use the same for consistency. iPhone users expect to see "Wi-Fi".

However, there could be a regional difference...

Note: iOS devices sold in China may use the term Wireless LAN (WLAN) instead of Wi-Fi.

Reference: http://support.apple.com/kb/ts1398

(EDIT: For comparison, my Nokia E65 (sold in the UK) uses the terms "WLAN" or "Wireless LAN" exclusively, no mention of "Wi-Fi" or its derivatives.)


In the past it was "Wi-Fi", but the current trend is toward "wifi".

It's a little like e-Mail => eMail => email.

December 2015 update: A Google search now results in 41% more occurences of "wi-fi" than "wifi". Apparently the trend has reversed.

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    Could you provide some kind of reference to back up this claim please? Sep 14, 2012 at 14:43
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    This question was closed, inappropriately in my opinion, because it is "unlikely to help any future visitors." But you can Google "wi-fi" and "wifi", and you'll find that wifi has more hits. "Wi-fi" used to have more hits.
    – xpda
    Sep 17, 2012 at 3:27
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    I believe this question should be reopened. Can we say two years later that this trend been confirmed?
    – Mari-Lou A
    Sep 11, 2013 at 8:06
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    Even 4 years later with 27,000 views, this question is still "unlikely to help any future visitors".
    – xpda
    Mar 31, 2015 at 18:29
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    I've never seen e-Mail (with capital 'M') being common (or eMail either for that matter), and I don't remember it being the original. I'm sure I've seen it (or them) here and there, but chalked it up to people who are not a part of mainstream tech culture, a little bit like people who spell OS X as OSX or iOS as Ios Do you have any evidence that that was the original? My memory is that "e-mail" was the original (and it is the convention I still adhere to).
    – iconoclast
    Aug 19, 2016 at 2:09

According to publications like PC Magazine which would be more likely to use the "correct" spelling, the word is spelled:


A wireless local area network (WLAN) technology that conforms to the IEEE 802.11 standard. Wi-Fi is the wireless counterpart to the wired Ethernet network, which is the ubiquitous local area network (LAN) technology used in companies and homes worldwide. A Wi-Fi logo from the Wi-Fi Alliance certifies that network devices comply with the IEEE 802.11 standards.

However, WordNet from Princeton spells it WiFi. Based on a quick Google search, most official sites (such as Starbucks) use either WiFi or Wi-Fi. Since there is so much variation, wifi looks fine as it is, and people understand the forms wifi, WiFi, Wi-Fi and possibly Wifi, you could use any of them and still be fine. The key to your use is that you are aiming towards being understood, not necessarily maintaining the trademark. (If we all maintained trademarks, we wouldn't refer to Blackberries instead of Blackberry mobile devices.)

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    I really think this is one case where even in quotes, the word "correct" is a bit misplaced. Also note that even after many decades, usage for the analogous hifi/hi-fi is still split pretty much 50-50, so it ain't going anywhere fast. Sep 9, 2011 at 0:23
  • I think all variations of wifi are understandable. I'm not worried about sounding strange to my users. I'm just wondering if a particular variant would result in legal issues because it refers to a company's trademark rather than a general concept.
    – JoJo
    Sep 9, 2011 at 0:25
  • Prepare yourself for the possibility that the freelance journalist writing for PC Magazine arbitrarily chose the orthography that they preferred and nobody cared terribly much. Whether that makes it "correct" or not I think is a largely pointless and/or unanswerable question... Sep 9, 2011 at 1:18
  • It is highly unlikely that PC Magazine left its style decision for Wi-Fi to a freelance journalist who happened to be writing the entry for that topic in its "PC Encyclopedia"—especially since the piece was posted in the days when PC Magazine still had (I believe) a copyediting staff. I know for a fact that PC World (which for years was the biggest print rival of PC Mag) maintained a house word list that was several hundred pages long, and that Wi-Fi appeared on that list only after considerable research and consultation with various in-house editors.
    – Sven Yargs
    Apr 1, 2015 at 0:56

The correct spelling is Wi-Fi even if wifi is most used.

Google Trends clearly shows this: wifi vs Wi-Fi on google trends

If it's technical document, I would use Wi-Fi. But, if SEO is very important, I would use wifi (+other keywords to create a long tail keyword).

Valeria (anyway, on the Tanaza website we use only Wi-Fi)

  • This may be the most practical answer, but I suppose people on this site are not terribly concerned about practical matters, hence the fact that I'm the first to vote up.
    – iconoclast
    Aug 19, 2016 at 2:17
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    Google search term frequencies are not necessarily a good indicator of what is most used. These track what people entered into the search box, and it is quite plausible that even people who prefer the term "Wi-Fi" tend to type the search term "wifi" just for convenience. Without making the distinction, you shouldn't assume that search term frequency is an accurate reflection of usage frequency.
    – Tripartio
    Jan 21, 2018 at 19:10
  • "on the Tanaza website we use only Wi-Fi" - Although you seem to have switched over to mostly "WiFi" more recently? And (presumably in your attempt at SEO) on some pages you seem to randomly switch between "WiFi" and "Wi-Fi", which is rather inconsistent (and confusing) and portrays a less professional image to your readers in my opinion.
    – MrWhite
    Sep 14, 2018 at 19:52

According to Google's Developer Documentation Style Guide, it should be spelled Wi-Fi.


Wi-Fi is a trademark of the Wi-Fi Alliance. The name is sometimes written as WiFi, Wifi, or wifi, but these are not approved by the Wi-Fi Alliance. -- Source

This is a case similar to facial tissues being generically referred to as "Kleenex". There are many examples of a trademark becoming a generic term, in which case the original capitalization or other unique stylization become lost or varied. Other common examples include Aspirin, Cellophane, Dry ice, Escolator, Kerosene, Lanolin, Laundromat, Linoleum, TelePrompTer, Thermos, Trampoline, and Videotape. -- Source

The official term is "Wi-Fi". However, when English users treat a trademark generically, the "rules" for what is proper become the relative prevalence of the unofficial usage.

  • So theoretically in something like technical documentation which accompanied software, one would need to acknowledge that "Wi-Fi" is a registered trademark of the Wi-Fi Alliance. We're going with "Wired" and "Wireless" [Network].
    – Kingsley
    Mar 1 at 0:50

FWIW, Merriam Webster came down on "Wi-Fi" -- so if you want to cite a source, there it is.


I'd just like to weigh in here. It would seem that Windows 10 prefers "WiFi" in British English and "Wi-Fi" in American English. I noticed this when I changed my display language. I've probably used both orthographies from time to time, but I think I prefer the hyphenated version.


For modern practical style I almost always go with The Guardian, which has wifi.


Apple and Google style guides both still say Wi-Fi.

Apple: "Wi-Fi. Not wifi, wi-fi, or WiFi."

Google: "Wi-Fi; not wifi or WiFi. When possible, instead use wireless."

  • Are Apple and Google both members of the Wi-Fi Alliance? If so that would explain their choice of styling. May 28, 2021 at 15:59

We use Wi-Fi as the generic term but are keeping an eye on the prevailing usage as with many tech terms.

An often-overlooked aspect of spelling/hyphenating terms is implied pronunciation. In "Wi-Fi," it's natural to read each "i" as "eye," whereas "wifi" is a bit ambiguous and some might read it as "wiffy."

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    I'm sorry, but are '[w]e' the usage panel at OED, the board at IBM, or the local darts team? Oct 3, 2019 at 18:10

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